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When many people think of asteroids, if they think of them at all, they tend to think of the asteroid (or comet) that ended the reign of the dinosaurs, or movies where heroic astronauts try to deflect an on-coming civilisation-killing rock. More rarely they will think of the tiny Hayabusa spacecraft struggling to return from asteroid Itokawa, or the images of the asteroid Vesta beamed back from the Dawn spacecraft.

Many people don't realise that the vast majority of asteroids are not harbringers of doom and that you can see (at least some of) them from your back yard.

So it is with asteroid 2012 DA14. While some people are reacting to news of this record-breaking asteroid with trepidation, thousands of amateur astronomers around Australia are preparing to watch its historic flyby on the morning of 16 February with growing excitement.

You can watch it too. It won't be bright enough to see with the unaided eye, but you don't need sophisticated equipment to see this 40-or-so-metre rock zoom over head.

All you need is a pair of reasonably strong binoculars.

With binoculars (I use 10x50s), there is a narrow window for time between when the oncoming asteroid becomes bright enough to see and when the advancing dawn washes the tiny dot out.

Yes, that's the bad news; you have to get up before dawn to see a tiny point of light slide gently amongst the stars. Although the asteroid is roughly the size of many a sports field, it is so far away that in all but the biggest research-grade telescopes it will be no more than a dot. Although close in cosmic terms, at its closest the asteroid is never nearer than 27,000 kilometres away from us, nearly 100 times further away than the International Space Station and around two Earth diameters away.

Get some perspective

The scale of the solar system constantly confounds us. To get a better feel for the distances, get a large ball (soccer/volleyball/basketball etc) and place it in the centre of a room. This represents the Earth. Now get a tennis ball and place it 28 large ball diameters away (you will need a very big room or a long hallway for this). This represents the Moon, the second ball's size is not to scale, but we are only looking at the distance here.

A sesame seed placed two large ball diameters away from the large ball represents 2012 DA14 at its closest (again, not to scale on size, 2012 DA14 would be microscopic at this scale) place another sesame seed 1/20 of the large ball diameter from the large ball. This represents the International Space Station. This should bring home the scale of the events we are seeing.

I have had people write to me worried that because you can see 2012 DA14 in binoculars it might swerve and hit us or Earth's gravity will act like a Hollywood black hole and suck the asteroid in. Using a model like the one I just described should give you some peace of mind (after all, Earth's gravity hasn't sucked up the myriad satellites and space junk that are much closer and slower than 2012 DA14).

Okay, why should you get up at dark o'clock to see a faint dot glide slowly through the sky? Well, because you can. Seriously, how many times do you get to see an asteroid that is zooming across the sky in real time? It's a challenge, but who isn't up for a challenge?

West is best

Your view of this asteroid depends on the state you are in. People in Western Australia have the best view seeing nearly the entire asteroid flyby.

There the asteroid becomes bright enough to see in binoculars around 2:30 am local time. Naturally, the amount of local light pollution is important; people in the countryside with dark skies will be able to see the asteroid earlier and easier than those in light polluted suburbs.

The central states have the next best views, with the brightest part of the pass occurring around astronomical twilight, when the skies are still quite dark (an hour and a half before sunrise, Darwin sees it before astronomical twilight at around 4:30 am local time Adelaide after at around 5:30 am).

The eastern states don't do as well. Brisbane, Sydney and Hobart have the brightest part of the pass deep in the twilight. Melbourne and inland sites such as Canberra see a little bit of the pass before it disappears in the twilight.

Where should you look?

Unfortunately the asteroid doesn't really pass anything bright and obvious when it is bright enough to see in binoculars. 2012 DA14 starts becoming bright enough to see in a rather undistinguished patch of sky in the south west. If you look south you will easily see the Southern Cross and the pointers. Follow an imaginary line drawn through the pointers down to about two-thirds of the way above the south-western horizon and look for anything faint moving slowly. as you watch the object should slowly brighten, this will be 2012 DA14.

The best time to pick up the asteroid is when it moves through the constellation Crater, it is reasonably bright then, and is moving relatively quickly, so will be quite recognisable.

When I say relatively quickly, it can actually be seen to move in binoculars, but compared to satellites or the International Space Station (which takes around five minutes to go from horizon to horizon), it positively creeps.

Crater is a fairly dim but recognisable cup-shaped constellation midway between the Southern Cross and Leo. 2012 DA14 will then continue to speed up and brighten as it heads towards the legs of Leo. For all but Western Australians this last part is hidden by the advancing twilight.

You can use this star chart based on Stellarium as a rough guide, but as the asteroid is so close, there will be some differences in location due to parallax. The times indicated are for Adelaide, but you will see roughly the same view at the equivalent local time at other sites (ie 5:00 am ACDST is 2:30 am AWST in Perth; allow for differing twilight times though). For charts that are specific for your location, go to the Heavens Above website, enter your location (you may need your latitude and longitude) and it will generate a chart specifically for your location.

You may want to try getting up early and locating the constellations a few nights beforehand, so that you are familiar with the sky. Also, if you have come from a bright room, you will need to allow around five minutes for your eyesight to become adapted to the dark so you can see faint objects.

It is a lot of effort to see a dim light crawl through the sky, but you will be rewarded with the knowledge that this is the closest a known asteroid has come to us and that you are seeing it yourself, live.

About the author:Dr Ian Musgrave is an avid amateur astronomer. He writes the weekly sky updates for ABC Science and is science adviser to iTelescope.net. When not staring at the sky he is an equally enthusiastic molecular pharmacologist at the University of Adelaide, Australia. You can follow him on Astroblog for daily posts about astronomy, biology and life, the Universe and everything.

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